Rank-and-file members have had their say in Labor's leadership contest, with ballots now closed and counting underway before Sunday's announcement.
The second and final piece of the leadership puzzle came into place when the ALP's members ballot closed at 5pm on Friday, with about 30,000 of the party's 43,000 members expected to have voted for either Bill Shorten or Anthony Albanese.
Mr Shorten, who is believed to have won Thursday's secret caucus vote, said he was "quietly confident" enough rank-and-file voters will support him to become Labor's new leader.
"But of course there's tens of thousands of people voting in a process that we've never seen before in Australia, in Australian political history," he told ABC Television earlier on Friday.
"So no one can really know until the vote is counted and, as I've said, I think if Anthony is elected he'll do a great job too."
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Under reforms introduced by former prime minister Kevin Rudd, caucus and members are given a 50-50 say in party leadership contests.
ALP members and supporters will be the first to know the result when party headquarters send out an email at about 2pm on Sunday.
Interim leader Chris Bowen, chief whip Chris Hayes and Labor's National President Jenny McAllister will then front the media.
Mr Shorten said the leadership process had helped cleanse the party of the rancour that marked Labor's past three years in government.
"I think the eyes of Australia are on this new process, where literally tens of thousands of people will have a say in who gets to run one of the major political parties in Australia," Mr Shorten said.
